Where can i get this game?

I'd judge that it's not real, actually.

it would be very interesting to see a fighting game like that tho. i can imagine it now... blue screen of death super >.> ho ho ho awesome

Its called M.U.G.E.N.

has someone really made the OS girls playable in a mugen system?

Nijikaku made a full game for MUGEN. Has almost all meme chars from 98 to waha. Even stuff from kusomiso.